package com.y.core.filter;

import java.io.IOException;
import java.util.Arrays;
import java.util.List;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.lang3.StringUtils;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

import com.baomidou.mybatisplus.toolkit.CollectionUtil;
/**
 * @show 为系统加入cross跨域功能
 * @author carl
 *
 */
public class CorsFilter implements Filter {

	protected Logger LOGGER = LogManager.getLogger(this.getClass());
    private String allowOrigin;
    private String allowMethods;
    private String allowCredentials;
    private String allowHeaders;
    private String exposeHeaders;

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
    	LOGGER.info("--------------为系统加入跨域支持-----------------");
        allowOrigin = filterConfig.getInitParameter("allowOrigin");
        allowMethods = filterConfig.getInitParameter("allowMethods");
        allowCredentials = filterConfig.getInitParameter("allowCredentials");
        allowHeaders = filterConfig.getInitParameter("allowHeaders");
        exposeHeaders = filterConfig.getInitParameter("exposeHeaders");
    }

    @Override
    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) req;
        HttpServletResponse response = (HttpServletResponse) res;
        if (StringUtils.isNotEmpty(allowOrigin)) {
            List<String> allowOriginList = Arrays.asList(allowOrigin.split(","));
            if (CollectionUtil.isNotEmpty(allowOriginList)) {
                String currentOrigin = request.getHeader("Origin");
                if (allowOriginList.contains(currentOrigin)) {
                    response.setHeader("Access-Control-Allow-Origin", currentOrigin);
                }
            }
        }
        if (StringUtils.isNotEmpty(allowMethods)) {
            response.setHeader("Access-Control-Allow-Methods", allowMethods);
        }
        if (StringUtils.isNotEmpty(allowCredentials)) {
            response.setHeader("Access-Control-Allow-Credentials", allowCredentials);
        }
        if (StringUtils.isNotEmpty(allowHeaders)) {
            response.setHeader("Access-Control-Allow-Headers", allowHeaders);
        }
        if (StringUtils.isNotEmpty(exposeHeaders)) {
            response.setHeader("Access-Control-Expose-Headers", exposeHeaders);
        }
        chain.doFilter(req, res);
    }

    @Override
    public void destroy() {
    	LOGGER.info("--------------跨域支持销毁-----------------");
    }
}